Plant for washing coal and other minerals



March 5, 19Z9 A. FRANCE PLANT FOR WASHING COAL AND OTHER MINERALS Filed Nov. 7, 1927 Zigi/9.

MM45-MMIV latented Mar. 5, 1929.

" UNITED.'y STATES 1,104,185 PATENT OFFICE;

- ANTOINEFRANCEY, OF LIEGE, BELGIUM.

PLANT FOR WASHING COAL AND OTHER MINERALS.

Application filed November 7, 1927, Serial No. 231,649, and in Belgium February 24, 1927.

the action of an alluvium forming sti-caio whereby the dense .particles are conveyed in the lower parts and the light particles in the upper parts, thebottom of the launder or launders being provided with slots in which the particles moving along the lower part of the lauiider can drop. In order to avoid the dropping of light particles into the slots intended normally to allow material of a determined minimum density to pass,- it is desirable lthat the dense layer formed and travelling upstream of these slots, be

freed from light particles, and that said layer shall have such a thickness and that said thickness shall 'be suiciently homogenous as to prevent light particles being driven with the dense particles throught-he slots. On the, other hand, the -material r which is to pass beyond the last slot should y be cleansed to the required extent, and freed from particles that could alter its composition. Now, the circumstances which determine the stage of layer-formation are yliable to vary on account of the general outline or shape of the effective transverse section of the launder, and according to the velocity acquired by the alluvium forming `stream which is moreover itself governed by they width and also by the shape given to the eifective section of the launder.

The resent invention relates to a launder, the eigective transverse section of which varies in shape at several points along a portion comprised between two successive slots, thus providing for a sequence of the phenomena in the order necessary for obtaining the required sorting or stratilication inside thelaunder. In accordance with re quirements', a' number of portions of launder,

each being a. portion comprised between twoV succeeding slots, may be given a similar shape, or a dissimilar shape if it be necessary, say, for example, by reason of variation in the average density of the material driven beyond each slot, due to the successive elimination of dense particles. The invention further relates to variation of the effective transverse section of the launder, at various points of a portion of it situated upstream of, and close to the first slot,

bulk ofand relates to the various embodiments which are hereinafter set forth by way of examples, with reference to the accompanying drawings. i

In these drawings, `Figui-es 1 and 2 are plans of parts of laundoi's having, at dilerent points along them, various shapes and sections.

Figure 3 is a vertical transverse sectional view of a launder, the effective widih of which is variable for different levels. The launder-illustrated by way of example in Iigure l comprises lirst a portion, the effective `section ofv which narrows progressively or converges in a downstream direction, then a iortion having an effective section of uii'i orin width, extending from` a point situated upstream of a slot 3 to a point downstream of7 the slot 3, next a portion having a section which diverrfes, still in a downstream direction and ,is iollowed by a portion of uniform width, which in turn is followed by a converging portion ending at a pointsomewhat upstream of the next slot 3 and is continued by a portion of uniform width ending ata point downstream of the slot 3 last referredto. Under these slots discharge pockets 4 may be eventually arranged. t l

in arrangement such as that above described will lend itself to the following sequence of phenomena-z From A to B the layer of ldense material travelling along the bottoni of the launder' will get gradually thicker, owingjto the gradual narrowing of the section; in this portionofithe launder, the. arrangement is also favourable to the separation bf any light particles that would be driven along Iin the bedding of dense material -from B to C, the dense material will have its thickness regulrized, as a result of the uniform section 'throughout that portion of the launder; by these means it isabove the apparatus,'drawn by a stream of greater velocity due to the narrowing of the launder in this position; then, from C to D, any dense particles which may have been drawn along in the upper part of the stream i throughout that portion of launder; then,

from E to F the layer of dense material will again get thicker and the separation of any light particles drawn along with the dense material will beefostered.

'Figure 2 shows a launder wherein the above explained arrangement, which is sy1n.

inetrical relative to the` axis, `has been replaced by the provision of a unilateral arrangement, the device having, at one side only, a shape like that above described, while the other side is uniform along the length of the launder. Although a technical result similar to the foregoing will, be obtained with this arrangement, it is, of course, less efficient than the bilateral arrangement.

Figure 3 is a cross section, wherein the effective section 1 of the launder is narrowest near its bottom, then diverges upwards, reaching its maximum width 2 at the top; such a cross-sectional variation can` be of profitable use in combination with the longitudinal variation, in order to give the launder a maximum capacity while providing for formation of a sufficiently thick bedding of schistous elements.

It should be understood that all of these embodiments are mere examples of carrying the invention into practice, and that, according to the quality of materials to be dealt with, or to the kind of sorting required, or the degree of perfection desired, launders of a Width varying lengthwise, in different ways, can be used; thus, if required sides having surfaces which are curved, rounded, winding or stepped and so on, can be used.

I claim:

A launder for classifying coal and other minerals according to specific gravity by means of a liquid conveying stream, which conveys the dense products to the lower parts and thev light products to the upper parts of the laundcr, in the bottom of which are arranged transverse slots for discharging the dense products moving in the lower parts of the launder, the inner section of said launder varying in the downstream direction so as to comprise consecutively a portion gradually widening from a point located downstream of a slot, a relatively wide portion of'constant section, a portion gradually narrowing up to a point located upstream of the next slot and a relatively narrow T)ortion of constant section extending from a point upstream to a point downstream of the last mentioned slot.

In testimony whereof I signed hereunto my name.

ANTOINE FRANCE. 

